Heat exchanger

ABSTRACT

A heat exchanger is provided. The heat exchanger may include a case in which a space is formed; a top cover coupled to a top of the case; a lower cover coupled to a bottom of the case; a first pipe that guides a first fluid to flow into the space and having an exit end, through which first fluid may come out into the space; a tube, through which a second fluid, which exchanges heat with the first fluid, may pass; and a second pipe that guides the first fluid discharged from the space and having an inlet end through which the first fluid may enter. The tube may have a spiral pipe portion positioned in the space and spirally wound. The inlet end may be positioned to be spaced from the top cover under the top cover. A height of the inlet end may be larger than a height of an upper end of the spiral pipe portion, and a height between an exit end and the lower cover may be smaller than a height between the inlet end and the lower cover. With this structure, it is possible to achieve a compact heat exchanger, while minimizing an installation space, and the first fluid may exchange heat with the spiral pipe portion of the tube as much as possible.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims priority under 35 U.S.C. §119 to Korean Application No. 10-2012-0068752, filed in Korea on Jun. 26, 2012, whose entire disclosure is hereby incorporated by reference.

BACKGROUND

1. Field

A heat exchanger is disclosed herein.

2. Background

Heat exchangers are known. However, they suffer from various disadvantages.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments will be described in detail with reference to the following drawings in which like reference numerals refer to like elements, wherein:

FIG. 1 is a schematic diagram of an air conditioner equipped with a heat exchanger according to an embodiment;

FIG. 2 is a side view showing an external appearance of a heat exchanger according to an embodiment;

FIG. 3 is a view showing an inside of the heat exchanger according to an embodiment;

FIG. 4 is a bottom view of a shell of FIG. 2;

FIG. 5 is a perspective view of a base of FIG. 2;

FIG. 6 is a plan view showing an inside of a heat exchanger according to an embodiment; and

FIG. 7 is a graph showing heat transfer amount according to a ratio of a height between an inlet and top cover of FIG. 3 and a height of a case.

DETAILED DESCRIPTION

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Where possible, like reference numerals have been used to indicate like elements, and repetitive disclosure has been omitted.

Heat exchangers are apparatuses that allow heat to transfer between two fluids and that are used for various purposes, such as cooling, heating, and supplying hot water. Heat exchangers may function as a waste heat recovery heat exchanger that recovers waste heat, a cooler that cools fluid at a high-temperature side, a heater that heats fluid at a low-temperature side, a condenser that condenses vapor, or an evaporator that evaporates fluid at a low-temperature side.

Various kinds of heat exchangers may be used, such as a fin-tube type heat exchanger having a tube, through which a first fluid flows, and fins formed on the tube; a shell-tube type air conditioner having a shell, through which a first fluid flows, and a tube, through which a second fluid that exchanges heat with the first fluid flows; a double tube type heat exchanger having an inner tube, through which a first fluid flows, and an outer tube, through which a second fluid that exchanges heat with the first fluid flows, that covers the inner tube; and a plate type heat exchanger, in which the first fluid and the second fluid flow with a heat transfer plate therebetween.

In a shell-tube type heat exchanger, a shell may be disposed to be horizontally long or extend horizontally, and a plurality of tubes may be disposed to be longitudinally long or extend longitudinally in the shell. A first fluid, for example, a cooling water, may flow into the shell and be discharged outside of the shell, and a second fluid, for example, a refrigerant, may be cooled by the first fluid while passing through the plurality of tube. A first fluid inlet, through which the first fluid may flow into the shell, may protrude outward at one side of the shell, and a first fluid inflow channel that guides the first fluid to the first fluid inlet may be connected to the first fluid inlet. A first fluid outlet, through which the first fluid may be discharged outside of the shell, may protrude outward at another side of the shell, and a first fluid discharge channel that guides the first fluid discharged from the first fluid outlet may be connected to the first fluid outlet.

FIG. 1 is a schematic diagram of an air conditioner equipped with a heat exchanger according to an embodiment. The air conditioner 1 of FIG. 1 may include a compressor 2, a first heat exchanger 4, an expansion device 6, and a second heat exchanger 8. The first heat exchanger 4 may allow heat exchange between a first fluid, for example, a cooling water, and a second fluid, for example, a refrigerant. The first fluid may function as a cooling fluid that absorbs heat of the second fluid. The air conditioner 1 may include the compressor 2, which compresses the second fluid; the first heat exchanger 4, which allows heat exchange between the second fluid and the first fluid; the expansion device 6, which expands the second fluid; and the second heat exchanger 8, which allows heat exchange between the second fluid and air.

The second fluid may sequentially pass through the compressor 2, the first heat exchanger 4, the expansion device 6, and the second heat exchanger 8. That is, the second fluid compressed by the compressor 2 may return to the compressor 2 after sequentially passing through the first heat exchanger 4, the expansion device 6, and the second heat exchanger 8. In this process, the first heat exchanger 4 may function as a condenser that condenses the second fluid, the second heat exchanger 8 may function as an evaporator that evaporates the second fluid, and the first fluid may absorb heat of the second fluid compressed by the compressor 2.

Alternatively, the second fluid may sequentially pass through the compressor 2, the second heat exchanger 8, the expansion device 6, and the first heat exchanger 4. That is, the second fluid compressed by the compressor 2 may return to the compressor 2 after sequentially passing through the second heat exchanger 8, the expansion device 6, and the first heat exchanger 4. In this process, the second heat exchanger 8 may function as a condenser that condenses the second fluid, the first heat exchanger 4 may function as an evaporator that evaporates the second fluid, and the first fluid may function as a heating fluid that transfers heat to the second fluid passing through the first heat exchanger 4.

The air conditioner 1 may further include a flow path selector (not shown), such as a valve, that allows the second fluid compressed by the compressor 2 to flow to the first heat exchanger 4 or the second heat exchanger 8. The air conditioner 1 may include a first circuit through which the second fluid compressed by the compressor 2 returns to the compressor 2 after sequentially passing through the flow path selector, the first heat exchanger 4, the expansion device 6, the second heat exchanger 8, and the flow path selector. The air conditioner 1 may include a second circuit through which the second fluid compressed by the compressor 2 returns to the compressor 2 after sequentially passing through the flow path selector, the second heat exchanger 8, the expansion device 6, the first heat exchanger 4, and the flow path selector. The first circuit may be a circuit for a cooling operation in which a room may be cooled by the second heat exchanger 8, in which the first heat exchanger 4 may function as a condenser that condenses the second fluid, and the second heat exchanger 8 may function as an evaporator that evaporates the second fluid. The second circuit may be a circuit for a heating operation in which a room may be heated by the second heat exchanger 8, in which the second heat exchanger 8 may function as a condenser that condenses the second fluid, and the first heat exchanger 4 may function as an evaporator that evaporates the second fluid.

The first fluid may be liquid-state fluid, such as water or antifreeze, and the second fluid may be various kinds of refrigerants, such as a Freon-based refrigerant or a carbon dioxide refrigerant generally used for air conditioners.

The compressor 2 may be a compressor that compresses the second fluid, such as a rotary compressor, a scroll compressor, or a screw compressor. The compressor 2 may be connected with the first heat exchanger 4 by a compressor outlet channel 3.

The first heat exchanger 4 may be a shell-tube type heat exchanger. The first heat exchanger 4 may include a shell, through which the first fluidmay pass, and a tube, through which the second fluid may pass. The first heat exchanger 4 may be connected with the expansion device 6 by a first heat exchanger-expansion device connection channel 5. The first heat exchanger 4 will be described in detail hereinbelow.

The expansion device 6 may be a capillary tube or an electronic expansion valve through which the second fluidmay expand. The expansion device 6 may be connected with the second heat exchanger 8 by an expansion device-second heat exchanger connection channel 7.

The second heat exchanger 8 may be a fin-tube type heat exchanger or a coil type heat exchanger through which the second fluidmay pass. The second heat exchanger 8 may include a tube, through which the second fluid may exchange heat with indoor air. The second heat exchanger 8 may further include fins, which function as heat transfer members, coupled to the tube. The second heat exchanger 8 may be connected with the compressor 2 by a compressor intake channel 9.

The air conditioner 1 may further include a heat treatment device 10 connected with the first heat exchanger 4. The heat treatment device 10 may function as a cooler that cools the first fluid, when the first heat exchanger 4 functions as a condenser that condenses the second fluid. Alternatively, the heat treatment device 10 may function as a heater that heats the first fluid, when the first heat exchanger functions as an evaporator that evaporates the second fluid. When functioning as a cooler, the heat treatment device 10 may include a cooling tower that cools the first fluid. The heat treatment device 10 may be connected with the first heat exchanger 4 by fluid discharge pipe 12 and fluid intake pipe 14. The first heat exchanger 4 may be connected with the heat treatment device 10 by the fluid discharge pipe 12, and the first fluid in the first heat exchanger 4 may be discharged to the heat treatment device 10 through the fluid discharge pipe 12. The first heat exchanger 4 may be connected with the heat treatment device 10 by the fluid intake pipe 14 and the first fluid in the heat treatment device 10 may enter the first heat exchanger 4 through the fluid intake pipe 14. A circulating mechanism, such as a pump, that circulates the first fluid to the heat treatment device 10 and the first heat exchanger 4 may be disposed in at least one of the heat treatment device 10, the fluid discharge pipe 12, and the fluid intake pipe 14.

The air conditioner 1 may further include an indoor fan 16 that returns indoor air to a room through the second heat exchanger 8.

The compressor 2, the first heat exchanger 4, the expansion device 6, the second heat exchanger 8, and the indoor fan 16 may be disposed in an air-conditioning device. Air in a room may be cool or heat the room by flowing to the second heat exchanger 8 through, for example, a duct and may then be discharged to the room through, for example, a duct. The heat treatment device 10 may be disposed not in the air-conditioning device, but rather, outside of the air-conditioning device and connected with one air-conditioning device through the fluid discharge pipe 12 and fluid intake pipe 14.

The compressor 2, the first heat exchanger 4, the expansion device 6, the second heat exchanger 8, and the indoor fan 16 may be distributed in a plurality of air-conditioning devices I and O. The first heat exchanger 4 and the indoor fan 16 may be disposed together in an indoor device I, and the compressor 2 and the first heat exchanger 4 may be disposed together in a compression device (or outdoor device).

The expansion device 6 may be disposed in at least one of the indoor device I or the compression device O. For the expansion device 6, one expansion device may be disposed in the indoor device I or the compression device O. Alternatively, a plurality of expansion devices 6 may be provided. The first expansion device may be disposed in the indoor device I, and the second expansion device may be disposed in the compression device O. The first expansion device may function as an outdoor expansion device, which is disposed closer to the first heat exchanger 4 than the second heat exchanger 8. The second expansion device may function as an indoor expansion device disposed, which is closer to the second heat exchanger 8 than the first heat exchanger 4.

The indoor device I may be installed in a room to cool or heat the room. A plurality of indoor devices I may be connected with the compression device O. The compression device O may be installed at or in, for example, a machine room, a basement, or a roof of a building. The compression device O may be connected with the heat treatment device 10 by the first discharge pipe 12 and fluid intake pipe 14.

The first heat exchanger 4 may be referred to as a heat exchanger in the following description.

FIG. 2 is a side view showing an external appearance of a heat exchanger according to an embodiment. FIG. 3 is a view showing an inside of the heat exchanger according to an embodiment. FIG. 4 is a bottom view of a shell of FIG. 2. FIG. 5 is a perspective view of a base of FIG. 2.

The heat exchanger 4 may include a shell 20, a first pipe 30 that guides a first fluid W, for example, a cooling water, into the shell 20, a second pipe 40 that guides the first fluid W outside of the shell 20, and a tube 70, through which a second fluid, for example, a refrigerant, that exchanges heat with the first fluid W may pass.

A space 18 may be defined in the shell 20. The space 18 may be filled up with the first fluid W and may receive the tube 70.

The shell may include a case 21, in which the space 18 is formed, a top cover 22 coupled to a top of the case 21, and a lower cover 23 coupled to a bottom of the case 21. The case 21 may be disposed to be vertically long or extend in a vertical direction, that is, a central longitudinal axis of the case may extend in a substantially vertical direction. The case 21 may be manufactured separately from the cover 22 and the lower cover 23, and may then be combined with the top cover 22 and the lower cover 23, without being integrally formed with at least one of the top cover 22 or the lower cover 23. When the case 21, the top cover 22, and the lower cover 23 are separately manufactured and then combined, an inner circumferential surface of the case 21, an underside of the top cover 22, and a top of the lower cover 23 may be easily coated with a coating fluid. When the inside of the shell 20 is coated, with the case 21 integrally formed with one of the top cover 22 or the lower cover 23, the coating fluid may not be uniformly spread throughout an inner wall of the case 21. In contrast, when the case 21, the top cover 22, and the lower cover 23 are separately manufactured, the coating fluid may be uniformly spread on the inner wall of the case 21. Thus, the case 21, the top cover 22, and the lower cover 23 may be combined, after the inner circumferential surface of the case 21, the underside of the top case 22, and the top of the lower cover 23 are coated.

The case 21 may have a hollow body 21 a with the space 18 therein, a first connecting portion 21 b coupled with the top cover 22, and a second connecting portion 21 c coupled with the lower cover 23. The hollow body 21 a may be formed in a hollow cylindrical shape.

The first connecting portion 21 b may protrude in a flange shape from an upper end of the hollow body 21 a. The first connecting portion 21 b may have fastening holes to fasten to the top cover 22 by fasteners 22 a, such as bolts. The second connecting portion 21 c may protrude in a flange shape from a lower end of the hollow body 21 a. The second connecting portion 21 c may have fastening holes to fasten to the lower cover 23 by fasteners 23 a, such as bolts.

The top cover 22 may be a plate. That is, the top cover 22 may be formed in a circular plate shape. A fastening hole corresponding to the first connecting portion 21 b may be formed through the top cover 22, and the top cover 22 may be coupled to the first connecting portion 21 b by the fasteners 22 a, such as bolts. The top cover 22 may close an upper open surface of the case 21.

The lower cover 23 may be a plate. That is, the lower cover 23 may be formed in a circular plate shape. A fastening hole corresponding to the second connecting portion 21 b may be formed through the lower cover 23, and the lower cover 23 may be coupled to the second connecting portion 21 c by the fasteners 23 a, such as bolts. The top cover 22 may close a lower open surface of the case 21.

The shell 20 may have the space 18 defined by the case 21, the top cover 22, and the lower cover 23, and the first fluid W may flow into the space 18 through the first pipe 30. The first fluid W may exchange heat with the tube 70 while flowing through the space 18.

A first pipe-through hole 24, through which the first pipe 30 may pass, may be formed in the shell 20. A second pipe-through hole 25, through which the second pipe 40 may pass, may be formed in the shell 20. Tube through-holes 26, through which the tube 70 may pass, may be formed in the shell 20. A number of the tube through-holes 26 may be the same as a number of tubes 70.

The first pipe 30 may guide the first fluid W to flow into the space 18, and an exit end 32, through which the first fluid may come out into the space 18 may be formed at the first pipe 30. The first pipe 30 may pass through the shell 20, such that the exit end 32 is positioned in the shell 20. A height L1 between the exit end 32 and the lower cover 23 may be smaller than a height L2 between an inlet end 42 and the lower cover 23, which are described below, of the second pipe 40. The first fluid W flowing in the shell 20 through the first pipe 30 may fill up from a lower portion in the shell 20. The first pipe 30 may be disposed such that the exit end 32 may be positioned at the lower portion in the shell 20. The portion, which may be positioned outside of the shell 20, of the first pipe 30 may be connected to the first fluid intake pipe 14 shown in FIG. 1.

The second pipe 40 may guide the first fluid W discharged from the space 18 and may have the inlet end 42 through which the first fluid W in the space 18 may enter the second pipe. The second pipe 40 may pass through the shell 20, such that the inlet end 42 may be positioned in the shell 20. The second pipe 40 may be disposed, such that the first fluid W at the lower portion in the shell 20 is not discharged through the second pipe 40, but the first fluid W at an upper portion in the shell 20 is discharged through the second pipe 40. The inlet end 42 may be positioned at the upper portion in the shell 20. The portion, which is positioned outside the shell 20, of the second pipe 40 may be connected to the first fluid discharge pipe 12 shown in FIG. 1. The inlet end 42 may be positioned under the top cover 22. The inlet end 42 may be spaced from the top cover 22. The inlet end 42 may be vertically spaced from the top cover 22. When a fluid level in the shell 20 is higher than the inlet end 42, the first fluid W may enter the second pipe 40 through the inlet end 42, and an air layer A, that is, a space containing air, may be formed between the inlet end 42 and the top cover 22. The heat exchanger 4 may not be provided with a specific air vent to discharge the air in the air layer A, and the top cover 22 may cover an entire upper opening of the space 18. The larger a height L3 between the inlet end 42 and the top cover 22, the larger a height of the air layer A between the first fluid W and the shell 20, and the less the height L3 between the inlet end 42 and the top cover 22, the larger the height of the air layer A between the first fluid W and the shell 20. When the height of the air layer A is smaller than an appropriate range, it is difficult to ensure a sufficient space, an internal pressure of the shell 20 may increase, and the shell may be frozen and burst, due to freezing of the first fluid W. However, when the height of the air layer A is larger than an appropriate range, material costs may increase due to the increase in height of the shell 20. Further, the first fluid W may leak from between the case 21 and the top cover 22 due to, for example, vibration of the heat exchanger 4. Thus, the height L3 between the inlet end 42 and the top cover 22 may be the height of the air layer A.

The first pipe 30, the second pipe 40, and the tube 70 may be disposed through one of the case 21, the top cover 22, or the lower cover 23. When the first pipe 30, the second pipe 40, and the tube 70 are disposed through the lower cover 23, the heat exchanger 4 may be easily cleaned. The upper cover 22 may be separated from the case 21, and the case 21 may be separated from the lower cover 23, with the first pipe 30, the second pipe 40, and the tube 70 fixed to the lower cover 23. A worker may easily clean the heat exchanger 4, with the upper cover 2 and the case 21 separated and the first pipe 30, the second pipe 40, and the tube 70 fixed to the lower cover 23. Considering easiness of cleaning the heat exchanger 4, the first pipe 30, the second pipe 40, and the tube 70 may be disposed through the lower cover 23.

The heat exchanger 4 may include a base 50 that supports the shell 20. The base 50 may have a fastening portion 52 to which the shell 20 may be fastened. The fastening portion 52 may be formed in a plate shape. The fastening portion 52 may be horizontally disposed or extend horizontallyunder the shell 20. The shell 20 may be placed on the fastening portion 52 or fastened to the fastening portion 52.

Fastening holes 54 to fasten the shell 20 with the fasteners 23 a, such as bolts, may be formed through the fastening portion 52. A through-hole 55, through which at least one of the first pipe 30 or the second pipe 40 may pass, may be formed through the fastening portion 52. The through-hole 55 of the fastening portion 52 may include a first pipe-through hole, through which the first pipe 30 may pass, and a second pipe-through hole, through which the second pipe 40 may pass. One through-hole 55 may be formed at the fastening portion 52, and the first pipe 30 and the second pipe 40 may pass together through one through-hole 55. When one through-hole 55 is formed at the fastening portion 52, the through-hole 55 may be formed to be horizontally long or extend horizontally. The through-hole 55 may be formed to be open at one side of the fastening portion 52. The through-hole 55 may be formed such that the lower portion of the first pipe through-hole 24 of the shell 20 and the lower portion of the second pipe through-hole 25 of the shell 20 are open. Tube holes 56, through which the tube 70 may pass may be formed in the fastening portion 52. The base 50 may have a support portion that supports the fastening portion 52. The support portion may include a plurality of legs 57, 58, 59, and 60 that supports the fastening portion 52. When the shell 20 is placed on the fastening portion 52, a portion of the first pipe 30, a portion of the second pipe 40, and a portion of the tube 70 may be positioned under the fastening portion 52 and extend under the shell 20.

The tube 70 may have a spiral pipe portion 74 positioned in the space 18 and spirally wound. A gap 73 may be defined between, a plurality of turns 71 and 72 of the spiral pipe portion 74. An entire shape of the spiral pipe portion 74 may be formed in a coil shape. The spiral pipe portion 74 may be positioned between the second pipe 40 and the shell 20 and may have a vertical central axis or vertically extending central longitudinal axis VX. The vertical central axis VX may be positioned at a portion where the portion of the first pipe 40 is positioned in the shell 20. The vertical central axis VX may coincide with a central axis or central longitudinal axis of the portion of the second pipe 40 positioned in the shell 20. The plurality of turns 71 and 72 may be wound, such that a distance L5 from the vertical central axis VX are the same. The spiral portion 74 may have at least ten or more turns. The spiral portion 74 may be wound continuously clockwise or counterclockwise. The plurality of turns 71 and 72 may be vertically spaced from each other, and the gap 73 may be defined between the plurality of turns 71 and 72. The first fluid W may flow into the space in the spiral portion 74 from the space between the shell 20 and the spiral portion 74 through the gap 73, or may flow into the space between the shell 20 and the spiral portion 74 from the space in the spiral portion 74 through the gap 73.

An upper end of the spiral pipe portion 74 may be higher than the inlet end 42 of the second pipe 40, to minimize the first fluid W that enters the inlet end 42 without exchanging heat with the spiral pipe portion 74, and the height L5 between the upper end of the spiral pipe portion 74 and the lower cover 23 may be smaller than the height L2 between the inlet end 42 and the lower cover 23. A height of the inlet end 42 may be larger than an upper end of the spiral pipe portion 74. The spiral pipe portion 74 may be disposed, such that a portion is positioned above the outlet end 32 of the first pipe 30. The exit end 32 may be positioned under the spiral pipe portion 74. A height of the exit end 32 may be smaller than a height of the lower end of the spiral pipe portion 74.

The tube 70 may have a straight pipe portion 75 that extends from the spiral portion 74 in a straight pipe shape. The straight pipe portion 75 may be bent at a lowermost turn of the spiral portion 74. The straight pipe portion 75 may be bent at an uppermost turn of the spiral portion 74. The straight pipe portion 74 may be disposed to extend substantially parallel to the vertical central axis VX.

FIG. 6 is a plan view showing an inside of a heat exchanger according to an embodiment. The tube 70 may include a plurality of tubes 70A and 70B disposed in the shell 20. The tubes 70A and 70B may have different distances from the vertical central axis VX to the spiral pipe portion 74. The pair of tubes 70A and 70B having different distances from the vertical central axis VX may be connected in series. Further, the pair of tubes 70A and 70B having different distances from the vertical central axis VX may be connected by a connection tube 70C. The connection tube 70C may be formed in a U-shape. The connection tube 70C may be disposed such that at least a portion is sunk in the first fluid W. The pair of tubes 70A and 70B and the connection tube 70C may constitute one heat transfer tube P. The second fluid may flow to the connection tube 70C after sequentially passing through the straight pipe portion 75 and the spiral portion 74 of any one of the pair of tubes 70A and 70B, and then, may flow to the outside of the shell 20 after sequentially passing through the spiral portion 74 and the straight pipe portion 75 of the other one of the pair of tubes 70A and 70B. The second fluid may exchange heat with the first fluid W while passing through any one of the pair of tubes 70A and 70B, exchange heat with the first fluid W while passing through the connection tube 70C, and then exchange heat with the first fluid W while passing through the other one of the pair of tubes 70A and 70B.

The spiral pipe portion 74 of one of the tubes 70A and 70B may be fixed with the first pipe 40. The tubes 70A and 70B may be fixed with the second pipe 40, with the tube closest to the second pipe 40 in contact with the second pipe 40. The tube closest to the second pipe 40 may be disposed so as to surround the second pipe 40. The tube closest to the shell 20 in the tubes 70A and 70B may be not in contact with the inner surface of the shell 20.

FIG. 7 is a graph showing heat transfer amount according to a ratio of a height between an inlet and the top cover of FIG. 3 and a height of a case. FIG. 7 is a dimensionless graph showing heat transfer performance according to a change in height ratio, with respect to a height ratio where the heat exchanger has an optimum heat transfer performance.

In the heat exchanger 4, a heat transfer amount of the first fluid and the second fluid may be measured while only the height ratio X changes, under conditions that a speed of current of the first fluid in the first pipe 30 is approximately 2.7 m/sec, a mass flow rate of the first fluid is approximately 1.6 kg/sec, and a volume flow rate of the first fluid is approximately 96LPM, in which when the height ratio X is about approximately 0.13, the heat transfer performance is highest and the dimensionless heat transfer amount according to the height ratio X when the height ratio of approximately 0.13 is 100% as shown as in FIG. 7.

In the heat exchanger 4, the height L3 between the inlet end 42 and the top cover 22 may be approximately 0.1 to 0.2 times the height L4 of the case 21. That is, in the heat exchanger 4, the ratio (X=L3/L4) of the height L3 between the inlet end 42 and the top cover 22 and the height of the case 21 may be 0.1 to 0.2.

When the height L3 between the inlet end 42 and the top cover 22 is less than approximately 0.1 times the height L4 of the case 21, the lower the height ratio, the less the heat transfer amount, and an area where the height ratio X is Oapproximately or less may be a rupture area A where a height of the air area is too small. When the height L3 between the inlet end 42 and the top cover 22 is above approximately 0.2 times the height L4 of the case 21, the heat transfer amount may reduce approximately 90% or less of a maximum heat transfer amount, and the height L3 between the inlet end 42 and the top cover 22 is approximately 0.1 to 0.2 times the height L4 of the case 21.

When the height L3 between the inlet end 42 and the top cover 22 is approximately 0.1 to 0.15 times the height L4 of the case 21, the heat transfer amount may be maintained at approximately 90% or more of the maximum heat transfer amount, and the height L3 between the inlet end 42 and the top cover 22 is set between approximately 0.1 to 0.15 times the height L4 of the case 21.

Hereinafter, operation of a heat exchanger having a configuration as described above will be discussed hereinbelow.

First, the second fluid may pass through the tube 70 and exchange heat with the first fluid while passing through the tube 70. The second fluid may be discharged outside of the heat exchanger 4 after sequentially passing through the tubes 70A and 70B.

The first fluid may flow to the lower portion in the shell 20 through the first pipe 30 and may flow up in the shell 20. The first fluid flowing in the space 18 through the exit end 32 of the first pipe 30 may pass through the gap 73 between the plurality of turns 71 and 72 of the spiral pipe portion 74 while rising in the shell 20, and may exchange heat with the tube 70. The first fluid exchanges heat with the entire spiral pipe portion 74 while rising to a level higher than the upper end of the spiral pipe portion 74, and then may flow into the inlet end 42 of the second pipe 40 at a position higher than the spiral pipe portion 74, and may be discharged to the outside of the heat exchanger 4 through the second pipe 40. The first fluid passing through the second pipe 40 may exchanges heat with the tube that is in contact with the second pipe 40, in contact with the tube that is in contact with the second pipe 40.

The heat exchanger allows heat exchange between the first fluid and the second fluid while keeping the optimum heat transfer amount and may be prevented from frozen to burst by an appropriate height of the air layer A even if the first fluid freezes due to too low air temperature.

In the heat exchanger 4, the case 21 may be separated from the lower cover 23 to clean the tube 70. A worker may clean the tube 70 with cleaning tools, such as a cleaning brush, without separating the first pipe 30, the second pipe 40, and the tube 70 from the lower cover 23.

Related art heat exchangers have a problem in that a large installation space is required, because the heat exchangers are disposed to be horizontally long and a plurality of straight pipe-shaped tubes is disposed, so that a number of tubes is large and a specific tube seat is required to fix the tubes, thus the structure is complicated and not compact in size.

Embodiments disclosed herein provide a heat exchanger that may include a case in which a space is formed; a top cover coupled to a top of the case; a lower cover coupled to a bottom of the case; a cooling water inflow or first pipe that guides a first fluid, for example, cooling water, flowing into the space and having an exit end through which cooling water comes out into the space; a tube, through which a second fluid, for example, a refrigerant, which exchanges heat with the cooling water, passes; and a cooling water discharge or second pipe that guides the cooling water discharged from the space and having an inlet end that the cooling water enters. The tube may have a spiral pipe portion positioned in the space and spirally wound. The inlet end may be positioned to be spaced from the top cover under the top cover. A height of the inlet end may be larger than a height of an upper end of the spiral pipe portion, and a height between an exit end and the lower cover may be smaller than a height between the inlet end and the lower cover.

The height between the inlet end and the top cover may be approximately 0.1 to 0.2 times a height of the case. The height between the inlet end and the top cover may be approximately 0.1 to 0.15 times the height of the case.

The cooling water inflow pipe, the cooling water discharge pipe, and the tube may extend under the lower cover through the lower cover. The spiral pipe portion may be positioned between the cooling water discharge pipe and the shell and may have a vertical central axis. The vertical central axis may be positioned at a portion where a portion of the cooling water discharge pipe is positioned in the shell.

The tube may include a plurality of tubes disposed in the shell, and the tubes may have different distances from the vertical central axis to the spiral pipe portion. The spiral pipe portion of one of the tubes may be in contact with the cooling water discharge pipe.

A height of the exit end may be smaller than the height of a lower end of the spiral pipe portion. The case may be vertically long or extend longitudinally.

Embodiments disclosed herein achieve a compact heat exchanger, while minimizing an installation space, and cooling water may exchange heat with the spiral pipe portion of the tube as much as possible. Further, embodiments disclosed herein minimize rupture due to freezing of the cooling water and increase a heat transfer amount between the cooling water and the refrigerant. Further, with embodiments disclosed herein, it is possible to clean the tube after separating the top cover and the case, and simply clean the tube without separating the cooling water inflow pipe, the cooling water discharge pipe, and the tube.

Any reference in this specification to “one embodiment,” “an embodiment,” “example embodiment,” etc., means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with any embodiment, it is submitted that it is within the purview of one skilled in the art to effect such feature, structure, or characteristic in connection with other ones of the embodiments.

Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art. 

What is claimed is:
 1. A heat exchanger, comprising: a case in which a space is formed; a top cover coupled to a top of the case; a lower cover coupled to a bottom of the case; a first pipe having an exit end through which a first fluid comes out into the space; a tube, through which a second fluid, which exchanges heat with the first fluid, passes; and a second pipe having an inlet end through which the first fluid is discharged from the space, wherein the tube has a spiral pipe portion positioned in the space, wherein the inlet end is positioned to be spaced from the top cover under the top cover, wherein a height of the inlet end is larger than a height of an upper end of the spiral pipe portion, and wherein a height between an exit end and the lower cover is smaller than a height between the inlet end and the lower cover.
 2. The heat exchanger of claim 1, wherein the height between the inlet end and the top cover is approximately 0.1 to 0.2 times a height of the case.
 3. The heat exchanger of claim 1, wherein the height between the inlet end and the top cover is approximately 0.1 to 0.15 times a height of the case.
 4. The heat exchanger of claim 1, wherein the first pipe, the second pipe, and the tube extend under the lower cover and through the lower cover.
 5. The heat exchanger of claim 1, wherein the spiral pipe portion is positioned between the first pipe and the case and has a substantially vertically extending central longitudinal axis.
 6. The heat exchanger of claim 5, wherein the central longitudinal axis is coxial with a central longitudinal axis of a portion of the first pipe positioned within the case.
 7. The heat exchanger of claim 5, wherein the tube comprises a plurality of tubes disposed in the case, and wherein the plurality of tubes has different distances from the central longitudinal axis to the spiral pipe portion.
 8. The heat exchanger of claim 7, wherein the spiral pipe portion of one of the plurality of tubes is in contact with the first pipe.
 9. The heat exchanger of claim 1, wherein a height of the exit end is smaller than a height of a lower end of the spiral pipe portion.
 10. The heat exchanger of claim 1, wherein a central longitudinal axis of the case extends in a substantial vertical direction.
 11. An air conditioner comprising the heat exchanger of claim
 1. 12. A heat exchanger, comprising: a case in which a space is formed; a first pipe having an end through which a first fluid enters the space; a tube, through which a second fluid, which exchanges heat with the first fluid, passes; and a second pipe having an end through which the first fluid is discharged from the space, wherein the tube has a spiral pipe portion positioned in the space, wherein the end of the second pipe is spaced from a top of the case, wherein a height of the end of the second pipe is larger than a height of an upper end of the spiral pipe portion, and wherein a height between the end of the first pipe and a bottom of the case is smaller than a height between the end of the second pipe and the bottom.
 13. The heat exchanger of claim 12, wherein the height between the end of the second pipe and the top of the case is approximately 0.1 to 0.2 times a height of the case.
 14. The heat exchanger of claim 12, wherein the height between the end of the second pipe and the top of the case is approximately 0.1 to 0.15 times a height of the case.
 15. The heat exchanger of claim 12, wherein the first pipe, the second pipe, and the tube extend through the bottom of the case.
 16. The heat exchanger of claim 12, wherein the spiral pipe portion is positioned between the first pipe and the case and has a substantially vertically extending central longitudinal axis.
 17. The heat exchanger of claim 16, wherein the central longitudinal axis is coxial with a central longitudinal axis of a portion of the first pipe positioned within the case.
 18. The heat exchanger of claim 16, wherein the tube comprises a plurality of tubes disposed in the case, and wherein the plurality of tubes has different distances from the central longitudinal axis to the spiral pipe portion.
 19. The heat exchanger of claim 18, wherein the spiral pipe portion of one of the plurality of tubes is in contact with the first pipe.
 20. The heat exchanger of claim 12, wherein a height of the end of the first pipe is smaller than a height of a lower end of the spiral pipe portion.
 21. The heat exchanger of claim 12, wherein a central longitudinal axis of the case extends in a substantial vertical direction.
 22. An air conditioner comprising the heat exchanger of claim
 12. 